# CVE-2020-13845: Execution Control List (ECL) Is Insecure in Singularity


- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 14 Jul 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-pmfr-63c2-jr5c, UBUNTU-CVE-2020-13845

## What is CVE-2020-13845?

CVE-2020-13845 is a high-severity vulnerability in n/a, published on 14 Jul 2020. 

### Official description

Sylabs Singularity 3.0 through 3.5 has Improper Validation of an Integrity Check Value. Image integrity is not validated when an ECL policy is enforced. The fingerprint required by the ECL is compared against the signature object descriptor(s) in the SIF file, rather than to a cryptographically validated signature.

Weakness: CWE-354 (Improper Validation of Integrity Check Value), CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2020-13845?

2 open source packages ship an affected version, including github.com/sylabs/singularity. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/sylabs/singularity` | Go | From 3.0.0 | 3.6.0 |
| `github.com/sylabs/singularity` | Go | From 3.0.0 | 3.6.0 |

Products: Sylabs Singularity.

## How do I fix CVE-2020-13845?

Upgrade github.com/sylabs/singularity to 3.6.0 or later.

## Is CVE-2020-13845 being exploited?

There is no known exploitation of CVE-2020-13845 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-33027](https://insights.sbomify.com/CVE-2021-33027/): Weak cryptography in n/a (critical 9.8)
- [CVE-2021-33622](https://insights.sbomify.com/CVE-2021-33622/): Other in n/a (critical 9.8)
- [CVE-2018-19295](https://insights.sbomify.com/CVE-2018-19295/): Sylabs Singularity Improper Input Validation (high 7.8)
- [CVE-2020-13846](https://insights.sbomify.com/CVE-2020-13846/): "Verify All" Returns Success Despite Validation Failures in Singularity (high 7.5)
- [CVE-2020-13847](https://insights.sbomify.com/CVE-2020-13847/): Other in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-13845 and fix it if it is affected.

What it is: CVE-2020-13845 is a high-severity vulnerability in n/a, published on 14 Jul 2020. 
Exploitation: There is no known exploitation of CVE-2020-13845 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/sylabs/singularity (Go): affected from 3.0.0; fixed in 3.6.0
- github.com/sylabs/singularity (Go): affected from 3.0.0; fixed in 3.6.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-13845/ (Markdown: https://insights.sbomify.com/CVE-2020-13845/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-13845
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-13845
- OSV: https://osv.dev/vulnerability/CVE-2020-13845

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-13845/
Summaries are generated and may contain mistakes; the official description above is the record.